PAULSBORO — Most of the more than 400 residents that were evacuated from their homes this week due to the Jefferson Street Bridge train derailment were allowed to return to their homes Friday afternoon following in-house and community wide air quality checks that found no trace of vinyl chloride left in the atmosphere.

Vinyl chloride‚ a colorless, flammable gas used in the creation of PVC plastics — leaked into Paulsboro’s air Nov. 30 when a Conrail train derailed and the Jefferson Street Bridge collapsed, sending four tanker cars into the water below.

Four of the derailed cars, and a fifth that remained on the tracks, contained the dangerous chemical. One of those cars sustained a gash in its hull during the accident, releasing the vinyl chloride.

More than 200 homes were evacuated between the accident and Tuesday. Residents were sent to hotels across Gloucester, Salem and Camden counties or have spent days with family and friends.

While they were expected to be kept out until at least Sunday, most of those families received good news Friday when their homes were checked one-by-one for any remaining traces of the chemical.

Lesli Butler has spent the past week in a Runnemede hotel with her 11- and 6-year-old children and she was thrilled to get clearance to come back home Friday afternoon.

“I’m going home!” she exclaimed, clutching paperwork that cleared her house and walking out of the Paulsboro Fire Department, which has been serving as the operation’s assistance center for residents.

She walked through her Madison Street house with inspectors from the Department of Environmental Protection and watched them test the air quality throughout her house and in the surrounding area.

Train derailment - Day 8, Paulsboro, Dec. 7, 2012Officials continue to secure and investigate the scene of last Friday's train derailment in Paulsboro, Friday, Dec. 7, 2012. Some evacuees were allowed back into their homes after the air quality was tested both outside and inside their homes. (Staff Video by Lori M. Nichols/South Jersey Times)

“I kept my fingers and toes crosses and hoped and prayed, and we got home,” she said. “I’m very grateful and very happy.”

Beginning at noon Friday, 15 evaluation teams brought residents to their homes and cleared them to move back in. It takes about 20 minutes to test each house thoroughly, and the majority of the homes were completed by Friday evening.

A handful of houses along North Commerce Street will not receive clearance to re-enter until further testing and the train removal is completed.

“I’m very happy (people can go home),” Paulsboro Mayor Jeff Hamilton said. “People can get back to their place and get Paulsboro back to where it’s got to be.”

Hamilton confirmed that residents of 170 evacuated homes have returned to their residences.

The train cars will remain in place until at least Sunday morning as the unified command, which is spearheaded by the U.S. Coast Guard, works to prepare the accident site for wreckage removal.

A 150-ton crane barge is in place on Mantua Creek, ready to begin lifting the train cars and shipping them out of the area. Workers need to first remove obstructions to the area, both above and under the water near the bridge.

According to U.S. Coast Guard Capt. Kathy Moore, the work is being completed by “talented, dedicated professionals.”

“It’s a tremendously complicated job,” she said.

While this work continues, legislators on the local, state and federal level have all weighed in on the incident, its command structure and how similar events can be prevented in the future.

The National Transportation Safety Board has been investigating the accident and found there were 23 “trouble tickets” issued within the last year regarding the Jefferson Street Bridge. Most dealt with minor issues such as debris on the tracks and broken lights, but at least two involved problems with the signals or alignment.

The NTSB has concluded that the freight train’s conductor received a red signal as he approached the swing bridge Friday morning, but crossed it following a visual inspection and permission from a dispatcher to do so.

“We forsake transportation infrastructure at our own peril,” he said. “A bridge built four years after the first trans-continental railroad opened cannot be expected to handle to needs of the 21st century global economy.

“There’s a commonly known prayer that asks God to help us understand the difference between circumstances we can control and those we cannot. Superstorm Sandy was an incident that was hardly under anyone’s control But I believe this derailment has much more to do with things that are in our control. Tolerance of the status quo is not acceptable.”